An existing burner is provided with a plurality of flame rings, and mixing chambers corresponding to the plurality of flame rings are intercommunicated, such that a mixed gas of fuel gas and air may circulate among the mixing chambers, and hence a mutual interference is prone to be generated among the plurality of flame rings. In addition, the burner also needs to be provided with a plurality of venturi tubes for supplying the mixed gas to the mixing chambers corresponding to the plurality of flame rings respectively, while a production process of the venturi tube is complicated, thereby resulting in an increased cost of the burner.